The present invention relates to a jaw implant, having a hollow body threaded on its inner side, said body comprising a threaded member acting on horizontally slidable pins.
Such an implant is for example disclosed in U.S. Pat. No. 2,745,180, whereby a thimble, driven by a screw element drives four cylindrical pins with a tapered end into the bone. The inner end of the retention pins is also symmetrically tapered, and the outer surface of the body is relatively smooth and tapered. The smooth surface of the body and the symmetrically tapered ends of the retention pins lead to an insufficient anchorage of the implant. The contact line between the tapered end of the thimble and the tapered end of the retention pins transmits forces poorly.
U.S. Pat. No. 2,857,670 discloses a similar implant, having a multitude of retention pins in different levels, thus complicating very much the fabrication of such small implants and necessitating an enormous precision of the parts.
U.S. Pat. No. 3,497,953 discloses a similar implant, wherein four bendable elements are driven by a complicated mechanism into the bone. In view of the small dimensions of such implants the bendable elements and the driving mechanism are critical parts, leading to a costly production.
German Offenlegungsschrift No. 3,421,056 discloses a jaw implant with a cylindrical full body having supporting ribs at its surface. This type of implant needs a long body for sufficient anchorage and is not suited for patients with thin jaw bones.